首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   475篇
  免费   38篇
  国内免费   7篇
管理学   86篇
民族学   5篇
人口学   14篇
丛书文集   22篇
理论方法论   26篇
综合类   311篇
社会学   44篇
统计学   12篇
  2024年   2篇
  2023年   5篇
  2022年   10篇
  2021年   14篇
  2020年   25篇
  2019年   29篇
  2018年   16篇
  2017年   24篇
  2016年   17篇
  2015年   16篇
  2014年   35篇
  2013年   21篇
  2012年   31篇
  2011年   50篇
  2010年   19篇
  2009年   18篇
  2008年   30篇
  2007年   31篇
  2006年   26篇
  2005年   24篇
  2004年   16篇
  2003年   23篇
  2002年   7篇
  2001年   10篇
  2000年   6篇
  1999年   4篇
  1998年   2篇
  1997年   3篇
  1995年   1篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1981年   1篇
排序方式: 共有520条查询结果,搜索用时 31 毫秒
21.
In general cases, to find the exact upper bound on the minimal total cost of the transportation problem with varying demands and supplies is an NP-hard problem. In literature, there are only two approaches with several shortcomings to solve the problem. In this paper, the problem is formulated as a bi-level programming model, and proven to be solvable in a polynomial time if the sum of the lower bounds for all the supplies is no less than the sum of the upper bounds for all the demands; and a heuristic algorithm named TPVDS-A based on genetic algorithm is developed as an efficient and robust solution method of the model. Computational experiments on benchmark and new randomly generated instances show that the TPVDS-A algorithm outperforms the two existing approaches.  相似文献   
22.
Although the organizational structures and operating procedures of state substance abuse prevention systems vary substantially across states, there is scant empirical research regarding approaches for rigorous assessment of system attributes and which attributes are most conducive to overall effectiveness. As one component of the national cross-site evaluation of the SPF State Incentive Grant Program (SPF SIG), an instrument was developed to assess state substance abuse prevention system infrastructure in order to measure infrastructure change and examine the role of state infrastructure in achieving prevention-related outcomes. In this paper we describe the development of this instrument and summarize findings from its baseline administration. As expected, states and territories were found to vary substantially with respect seven key characteristics, or domains, of state prevention infrastructure. Across the six domains that were assessed using numeric ratings, states scored highest on data systems and lowest on strategic planning. Positive intercorrelations were observed among these domains, indicating that states with high capacity on one domain generally have relatively high capacity on other domains as well. The findings also suggest that state prevention infrastructure development is linked to both funding from state government and the presence of a state interagency coordinating body with decision-making authority. The methodology and baseline findings presented will be used to inform the ongoing national cross-site evaluation of the SPF SIG and may provide useful information to guide further research on state substance abuse prevention infrastructure.  相似文献   
23.
Public participation in the planning and design of major public infrastructure and construction (PIC) projects is crucial to their success, as the interests of different stakeholders can be systematically captured and built into the finalised scheme. However, public participation may not always yield a mutually acceptable solution, especially when the interests of stakeholders are diverse and conflicting. Confrontations and disputes can arise unless the concerns or needs of the community are carefully analysed and addressed. The aim of the paper is to propose a systematic method of analysing stakeholder concerns relating to PIC projects by examining the degree of consensus and/or conflict involved. The results of a questionnaire survey and a series of interviews with different entities are provided, which indicate the existence of a significant divergence of views among stakeholder groups and that conflicts arise when there is a mismatch between peoples’ perception concerning money and happiness on the one hand and development and damages on the other. Policy and decision-makers should strive to resolve at least the majority of conflicts that arise throughout the lifecycle of major PIC projects so as to maximise their chance of success.  相似文献   
24.
The internet and other digital networks in the U.S. (and beyond) remain essentially an upgrade of the national telephone network built by AT&T over the first half of the twentieth century, and digital payment remains tethered to telephony at the level of infrastructure. Telephone history also continues to inform digital payment at the level of interface. Debit card readers feature a keypad nearly identical to those introduced (also by AT&T) to the dialling public a half-century ago on touch-tone telephones. In this essay I highlight the development of the touch-tone keypad as a transformative payment technology. There have been three great leaps forward in the history of telephone interface: the dial, the keypad and the touch screen. Each corresponds to a period of technological transformation in the telephone industry and society more broadly: the rotary dial and automation, touch-tone keypads and digitization, and touch screens and computerization. The successful careers of the dial and the keypad, especially when read in tandem, suggest that touch screens will alter the everyday economics of retail payment even more radically than its predecessors. I also describe a broader trajectory of digital naturalization, whereby telephone numbers have proliferated into a personal identification number, passwords and a plethora of personalized information. Payments increasingly circulate today as subsets of personal information within the vast sea of big data. Payment apps are demonstrating a capacity to reorganize retail transactions on a scale as vast as any technology since the cash register. The history of retail payment finds the point of sale heading from the till into shoppers’ pockets. As a result, consumers are increasingly shouldering the costs of purchasing, maintaining, upgrading and securing the technology used for everyday transactions.  相似文献   
25.
近年来,政府债务危机频频爆发,国务院办公厅下文要赋予地方政府适度举债融资权,规范地方政府的举债融资机制.政府与社会资本合作模式(P P P模式)被列入规范政府举债融资机制之中,该举措对于化解地方政府债务压力,缓解公用基础设施建设资金短缺发挥重要作用.因此需要对PPP模式适用于政府债务领域的可行性和必要性进行分析,在缓解政府债务的PPP具体模式中加以选择,并从法律层面保障PPP模式的实施.  相似文献   
26.
为了解决目前远程教育中IT服务存在的问题,对网络教育学院的IT服务和信息技术基础设施库(ITIL)标准进行了深入研究,提出了适合远程教育的IT服务管理(ITSM)模型,并以北京邮电大学网络教育学院为例,重点描述了模型中的需求分析及需求变更管理、远程教育组织结构设计、应用和基础设施监控管理三个核心流程的设计与实施,该模型为远程教育IT服务提供了解决方案。  相似文献   
27.
秦国能统一中国,除了政治、军事方面的原因,还有一个被史学界忽略的因素:建立了完整的经济战略体系。这套体系包括后勤基地建设、经济改革以及交通路网络。这套体系为秦统一战争提供了巨大的后勤保障。  相似文献   
28.
This paper considers the problem of devising a single stage procedure for selecting the treatment combination associated with the largest interaction in a two-factor rfx× c experiment having independent normally distributed observations with common known variance. The intuitive procedure based on the best linear unbiased estimators of the population interactions is employed. Initially an indifference zone formulation is used; the problem of determining the least favorable configuration is reduced to a nonlinear programming problem with log concave objective function and a convex polytope as feasible region. A solution technique is introduced in the context of an illustrative example. The problem is also considered using a preferred population formulation; this approach requires a strengthened version of the indifference zone probability requirement. It is shown that the same sample size guarantees this requirement as does the earlier one.  相似文献   
29.
Interdependency analysis in the context of this article is a process of assessing and managing risks inherent in a system of interconnected entities (e.g., infrastructures or industry sectors). Invoking the principles of input-output (I-O) and decomposition analysis, the article offers a framework for describing how terrorism-induced perturbations can propagate due to interconnectedness. Data published by the Bureau of Economic Analysis Division of the U.S. Department of Commerce is utilized to present applications to serve as test beds for the proposed framework. Specifically, a case study estimating the economic impact of airline demand perturbations to national-level U.S. sectors is made possible using I-O matrices. A ranking of the affected sectors according to their vulnerability to perturbations originating from a primary sector (e.g., air transportation) can serve as important input to risk management. For example, limited resources can be prioritized for the "top-n" sectors that are perceived to suffer the greatest economic losses due to terrorism. In addition, regional decomposition via location quotients enables the analysis of local-level terrorism events. The Regional I-O Multiplier System II (RIMS II) Division of the U.S. Department of Commerce is the agency responsible for releasing the regional multipliers for various geographical resolutions (economic areas, states, and counties). A regional-level case study demonstrates a process of estimating the economic impact of transportation-related scenarios on industry sectors within Economic Area 010 (the New York metropolitan region and vicinities).  相似文献   
30.
整合财政支农资金加大农村基础设施投入力度   总被引:5,自引:0,他引:5  
由于历史原因和体制惯性,“三农”投入,特别是财政支农资金的投入存在许多问题,多头管理、分散使用、效率低下的现象十分突出。继续加大对“三农”尤其是农村基础设施的投入力度,推进财政支农资金整合,提高财政支农的政策效应和制度效应,对发展现代农业,建设社会主义新农村意义重大。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号